The installation steps depend on whether your OnePlus 9 is currently running Android 12 or Android 13. Newer OxygenOS versions hide the local upgrade option, requiring a workaround application. Step 1: Prepare the Firmware File
This guide is for educational purposes only. Proceed at your own risk.
: Go to Settings > About Device and note down your specific model number (e.g., LE2111, LE2113, LE2115). You must download the rollback file that matches your exact region. downgrade oneplus 9 to android 11 exclusive
The Ultimate OnePlus 9 Downgrade Guide: Returning to the OxygenOS 11 Glory Days
Before starting, ensure you have taken the following precautions: The installation steps depend on whether your OnePlus
Many users found that Android 12 led to excessive battery drain (SOT as low as 2.5 hours), which was often resolved by rolling back.
Why this is "exclusive": Most guides tell you to use the stock system updater. It doesn't work on Android 13. The APK method works exclusively for cross-version downgrades. Proceed at your own risk
Here is the hard truth: Whether you use the local upgrade method or the MSM Download Tool, your internal storage will be erased. As noted by OnePlus community experts, rollback packages are designed specifically because “the upgrade method will erase all the contents of the phone, please be sure to backup first”.
Once you are on OxygenOS 11, the phone may immediately ask to update back to Android 12/13.
to Android 11 (OxygenOS 11), you must use a specific provided by OnePlus . This process will erase all data on your phone, so backing up your files is essential. Preparation
or 9 Pro) and region from sources like the OnePlus Community forums or SourceForge . Find the downloaded file in your file manager. If it ends in .jar , rename it to end in .zip .